HORN EXPEDITION—REPTILIA. 
121 
In the Vol. I., p. 75, H. derbiana is flistinguislied from H. by7ioei by 
the following charactei’s :— 
(i.) Dorsal tubercles generally less regularly arranged, more distant 
from one another, those of one series being separated by inter¬ 
spaces at least equal to their length. 
(ii.) Prajanal pores four or six. * 
(iii.) Colour.—Light brown above, spotted or marlded with darker ; 
some of the tubercles sometimes whitish; a dark temporal 
streak ; lower surfaces whitish. 
In H. bynoei on the other hand — 
(i.) Dorsal tubercles placed close together in twelve to fourteen very 
regular longitudinal series. 
(ii.) Prieanal pores five. 
(iii) Colour.—Light brown above; seven dark transverse bands, 
broader than the interspaces between them, from nape to base 
of tail; a U-shaped dark streak from eye to eye over the nape; 
lower surfaces dirty white. 
(i.) The appearance of irregularity in the arrangement of the tubercles depends 
to some extent on the lack of regularity in colour. In all specimens which are 
irregularly spotted or marbled, and in which some of the tubercles are whitish, the 
appearance of irregularity is accentuated. 
Apart from this, however, we found the irregularity to be as great in specimens 
which in number of prieanal pores and in colour agreed with H. bynoei, as in 
specimens which in these particulars agreed with H. derbiana, 
(ii.) We found individuals with faint but regular colour bands, possessing 
respectively four, five and six prseanal pores; and we also met with individuals in 
which the colour was much broken up, and which possessed five, six and seven 
(one individual) pores respectively. 
(iii.) In the specimens from King’s Sound in which the lines of tubercles were 
most regular and compact, the dark colour bands were pronounced, regular and 
broad, there being only five of these in the space between the nape and the base 
of the tail. 
From the specimens examined a complete series can be arranged in which 
the colour bands vary gradually from being dark and distinct to faint and 
R 
